Evidence of economic development revealed in centennial scale sedimentary records of organic pollutants in Huguangyan Marr Lake.

Sedimentary records of polycyclic aromatic hydrocarbons (PAHs) and phthalates could reflect energy consumption and industrial production adjustment. However, there is limited knowledge about their effects on variations of PAH and phthalate compositions in the sediment core. The PAH and phthalate sedimentary records in Huguangyan Maar Lake in Guangdong, China were constructed, and random forest models were adopted to quantify the associated impact factors. Sums of sixteen PAH (∑16 PAH) and seven phthalate (∑7 PAE) concentrations in the sediment ranged from 28.8 to 1110 and 246-4290 µg/kg dry weight in 1900-2020. Proportions of 5-6 ring PAHs to the ∑16 PAHs increased from 32.0 %-40.7 % in 1900-2020 with increased coal and petroleum consumption, especially after 1980. However, those of 2-3 ring PAHs decreased from 30.7 % to 23.6 % due to the biomass substitution with natural gas. The proportions of bis (2-ethylhexyl) phthalate to the ∑7 PAEs decreased from 52.3 %-29.1 % in 1900-2020, while those of di-isobutyl phthalate increased (13.7 % to 42.3 %). The shift from traditional plasticizers to non-phthalates drove this transformation, though the primary plastic production is increasing. Our findings underscore the effectiveness of optimizing energy structures and updating chemical products in reducing organic pollution in aquatic environments.

Construction of carbon nanospheres: A rational design based on BS-12 @ LiCl.

Nanocarbons have potential applications in almost all areas of materials science. While we have appreciated the various discoveries and applications of many nanocarbons, we recognize that the field remains challenging in terms of tunability. In this research, we report a new strategy for the self-assembly of surfactant @ salt from the concept of carbon nanostructure design, and introduce the concept of "separator". On the one hand, it allows the core and shell to be formed in one step. On the other hand, it allows the ordered aggregates to remain in their original shape under thermal action. The surface morphology, degree of graphitization, elemental composition and surface chemical state, formation mechanism, and specific luminescent properties of carbon nanomaterials were investigated. TEM reveals that (dodecyldimethyl betaine) BS-12 @ LiCl carbon nanospheres with tunable size (from 55 nm to 70 nm) can be successfully synthesized. Raman and XRD show that the structure of carbon nanospheres has some defects and disordered carbon. XPS and FTIR analyses indicate that the defects present in the carbon nanosphere structure are related to the N and O elements. The detailed growth mechanism shows that the micelle structure in the system can be well adjusted by changing the concentration of surfactant. PL research demonstrates that the synthesized carbon nanospheres have UV luminescent properties. Most importantly, the method can be further developed into a general strategy for self-assembly using a variety of surfactants and "separators" as promising candidates for future practical applications of nanocarbon materials.

Insight into the adsorption behaviors and bioaccessibility of three altered microplastics through three types of advanced oxidation processes.

Advanced oxidation processes (AOPs) can significantly alter the structural properties, environmental behaviors and human exposure level of microplastics in aquatic environments. Three typical microplastics (Polyethylene (PE), polypropylene (PP), and polystyrene (PS)) and three AOPs (Heat-K2S2O8 (PDS), UV-H2O2, UV-peracetic acid (PAA)) were adopted to simulate the process when microplastics exposed to the sewage disposal system. 2-Nitrofluorene (2-NFlu) adsorption experiments found the equilibrium time decreased to 24 hours and the capacity increased up to 610 µg g-1, which means the adsorption efficiency has been greatly improved. The fitting results indicate the adsorption mechanism shifted from the partition dominant on pristine microplastic to the physical adsorption (pore filling) dominant. The alteration of specific surface area (21 to 152 m2 g-1), pore volume (0.003 to 0.148 cm3 g-1) and the particle size (123 to 16 µm) of microplastics after AOPs are implying the improvement for pore filling. Besides, the investigation of bioaccessibility is more complex, AOPs alter microplastic with more oxygen-containing functional groups and lower hydrophobicity detected by XPS and water contact angle, those modifications have increased the sorption concentration, especially in the human intestinal tract. Therefore, this indicates the actual exposure of organic compounds loaded in microplastic may be higher than in the pristine microplastic. This study can help to assess the human health risk of microplastic pollution in actual environments.

Correlation analysis between the in vivo bioavailability and in vitro bioaccessibility of nitro PAHs in soil: Application of simplified FOREhST in vitro methods based on the Chinese pharmacopoeia.

In this study, the relative bioavailability (RBA) of nitrated polycyclic aromatic hydrocarbons (NPAHs) in soil samples (n = 30) was assessed using an in vivo mouse model. Based on the correlation between the bioaccessibility data obtained from the Tenax improved traditional Fed ORganic Estimation human Simulation Test (FOREhST) in vitro method (TITF) and the bioavailability data obtained from in vivo experiments, the TITF method was further optimized and simplified by referring to the "Pharmacopoeia of the People's Republic of China: Volume IV, 2020" to adjust the formulation and parameters of the gastrointestinal fluid (GIF) in order to establish a simpler and lower cost in vitro method for the determination of the bioaccessibilities of NPAHs. The dose-accumulation relationship of the in vivo experiment showed that the linear dose-response was better in adipose tissue (R2 = 0.77-0.93), and the accumulation of NPAHs in adipose tissue was higher than that in kidney or liver tissue. Depending on the mouse adipose model, the NPAHs-RBA ranged from 1.88 % to 73.92 %, and a strongly significant negative relationship (R2 = 0.94, p < 0.05) was found between the NPAHs-RBA and Log Kow. The simplified experiment of the TITF showed that the composition of the GIF medium had a significant effect on the bioaccessibilities of NPAHs. The NPAH bioaccessibilities measured by the Tenax improved simplified FOREhST method (TISF) (9.0-36.5 %) were higher than that of the traditional FOREhST method (6.8-22.8 %) but significantly lower than that of the TITF method (16.8-55.2 %). With an increase in the bile concentration in the GIF (from 6 to 10 g/L), the bioaccessibilities of NPAHs increased from 9.0 to 36.5 % to 12.9-42.4 %. The accuracies of the four in vitro methods for predicting the bioavailabilities of NPAHs was in the following order: Tenax improved simplified FOREhST method with increased bile concentration (TITF-IB) (R2 = 0.54-0.87) ≈ TITF (R2 = 0.55-0.85) > TISF (R2 = 0.41-0.77) > FOREhST (R2 = 0.02-0.68). These results indicated that the simple in vitro method could also effectively predict the bioavailabilities of NPAHs.

Sediment core records and impact factors of polycyclic aromatic hydrocarbons in Chinese lakes.

Lake sediment is a natural sink for polycyclic aromatic hydrocarbons (PAHs). PAH sedimentation characteristics and their impact factors of Chinese lakes have mainly been qualitative assessed. However, quantitative impacts of PAH sedimentation from different factors have not been well analyzed. To fill this gap, we screened PAH sedimentation records from the literature, for 51 lakes in China and other regions of the world, to identify historical concentration variation and the impact factors of PAHs in different regions, in lake sediment. The results show that PAH concentrations in the sediment core in the selected Chinese lakes (478 ± 812 ng/g dry weight (dw)) were significantly lower than those in North America (5518 ± 6572 ng/g dw) and Europe (3817 ± 4033 ng/g dw). From 1900 to 2015, most of the lakes in China showed an increasing trend of PAH sedimentation concentrations, with the lakes in Southeastern China showed a decreasing trend of PAH concentration in the period of 2001-2015, which was later than the peak times shown in Western countries (1941-1970). The 2-3-ring PAHs were the main components in the sediment core of Chinese lakes, but the proportion to the total PAHs decreased from 72% in 1900-1940 to 55% in 2001-2015. Generalized additive modeling (GAM) was adopted to simulate the associations between PAH sedimentation records and the impact factors. There are large regional variations of economic and industrial development in China. The impact factors of PAH accumulation in the lake sediments differ in different regions. However, population and the consumption of coal, pesticides, and fertilizer were identified to be the most important impact factors influencing PAH sedimentation. The Chinese government needs to strengthen control measures on pollutant discharge to reduce the anthropogenic impact of PAH sedimentation in lakes.

Occurrence and risk of iodinated X-ray contrast media in source and tap water from Jiangsu province, China.

Microcontaminants in the water environment have received increasing attention due to their adverse effects on human health and wildlife. However, iodinated X-ray contrast media (ICM), a type of microcontaminants, have not yet been systematically documented in source and tap water. This study investigated ICM in water samples via a sampling activity from 25 drinking water sources and their corresponding 30 household taps in south-central Jiangsu Province, China. The total concentrations of ICM ranged from 14.2 to 138.5 ng/L in source water and 3.7 to 101.3 ng/L in tap water, respectively. The calculated average water treatment efficiency to remove ICM is 38.3% with large variation under different processes (ranging from 7.3% to 75.7%), which implied that ICM could not be effectively removed using current treatment technologies. By integrating other ICM into the predominant compound iohexol with relative potency factors, the health risks of total ICM through water consumption were assessed using the Monte Carlo simulation. The results concluded that the risk of ingesting ICM through tap water was not a major health concern for adults, teens, or children in the study area. Nevertheless, due to the lack of long-term toxicity data relevant for humans for ICM, this risk may be underestimated, which requires further research.

Phthalate pollution and migration in soil-air-vegetable systems in typical plastic agricultural greenhouses in northwestern China.

Phthalate pollution in plastic greenhouses (PGs) has aroused concerns. However, mechanisms and factors of vegetables planted in PGs (VPGs) accumulating phthalates from soil and air are unclear. To fill the gap, 19 PGs in Shaanxi, the largest vegetable production province in northwestern China, were selected to probe this issue. 35 soil samples, 48 air samples, and 26 VPG samples were collected in winter and summer. Medians of sum of 7 phthalate concentrations (∑7 PAEs) in PG soil, air, and VPGs were 73.9 µg kg-1, 5300 ng m-3, and 1053 µg kg-1 dry weight, respectively. ∑7 PAE concentrations in PG environmental media in winter were higher than summer, with the significant difference in VPGs. Sum concentrations of bis (2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DnBP) accounted for 76.8% and 82.3% of the ∑7 PAEs in soil and VPGs. DnBP and DEHP concentrations in VPGs were significantly correlated to those in air and soil, with correlation coefficients (R) of 0.89 and 0.96 to air and 0.68 and 0.59 to soil. Log-transformed soil-air partition coefficient (log KSA) and fugacity fraction (log ff) of DnBP decreased while log KSA and log ff of DEHP increased from winter to summer, though DnBP in soil volatilized to air while DEHP in air sank to soil within the year. These issues were caused by air temperature changes and the application of plastic films. Furthermore, DnBP concentrations in VPGs were positively correlated to KSA values of DnBP (R = 0.87) while those of DEHP were negative (R = -0.82). Therefore, VPGs could uptake more phthalates from air than from soil, especially for edible parts of leafy and solanaceous VPGs. Applying phthalates free agricultural films and precision management such as adjusting air temperature in PGs could be considered to ensure VPG safeties.